Memory deficit has been reported in mice chronically treated with LPS [43] that agrees with our observation. 7 nAChR is now commonly recognized to mediate anti-inflammatory effect of acetylcholine in macrophages [2C3], microglial cells [4] and astrocytes [5]. 7(1-208) resulted in region-specific decrease of 7 and 42 and increase of 34 nAChRs, accumulation of A42 and activated astrocytes in the brain of mice and worsening Mouse monoclonal to LSD1/AOF2 of their episodic memory. Intravenously transferred 7 nAChR-specific-antibodies penetrated the brain parenchyma of mice pre-injected with LPS. Our data demonstrate that (1) neuroinflammation is sufficient to provoke the decrease of 7 and 42 nAChRs, A42 accumulation and memory impairment in mice IKK 16 hydrochloride and (2) 7(1-208) nAChR-specific antibodies can cause inflammation within the brain resulting in the symptoms typical for Alzheimer disease. Introduction Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels mediating fast synaptic transmission in muscle and autonomic ganglia [1]. In the brain, the nAChRs pre-synaptically control the release of several neurotransmitters, including dopamine, and influence cognition and memory, as well as establishment of nicotine dependence in smokers. In addition, nAChRs composed of 7 subunits are involved in regulating pro-inflammatory cytokines release in macrophages, brain astrocytes and microglia [2C5]. The decrease of the nAChR density in the brain neurons is observed upon Alzheimer disease (AD) [6], which is characterized by accumulation of oligomeric -amyloids IKK 16 hydrochloride (A) in the brain, memory impairments and loss of cognitive functions [7]. The AD is also accompanied by neuroinflammation, which often precedes the development of cognitive symptoms [8]. In spite of numerous investigations performed during the last decade the reason for the cholinergic deficit upon AD and its relation to neuroinflammation are still poorly understood. Previously we found that antibodies raised against the extracellular epitopes of 7 nAChR subunit stimulated pro-inflammatory IL-6 production in cultured U373 glioblastoma cells [9] and were able to decrease the 7 nAChR density in certain brain regions to impair episodic memory of mice [10]. Such antibodies were IKK 16 hydrochloride found in the blood of both healthy humans and AD patients and seemed to be elevated in patients with the early-onset AD [11]. In the present study, we asked a question if systemic inflammation induced by regular injections of bacterial endotoxin (lipopolysaccharide, LPS) can provoke the AD-like symptoms in mice and if LPS effects can be mimicked by 7 nAChR-specific antibodies. The results demonstrate that either LPS injections or immunizations with 7(1C208) stimulated astrocyte activation, re-distribution of nAChR subtypes, accumulation of A42 in the mouse brain and episodic memory impairment. Materials and Methods Ethics Statement We used female C57BL/6J mice starting from 3 months of age. The mice were kept in the animal facility of Palladin Institute of Biochemistry, Kyiv. They were housed in a quiet, temperature-controlled room (22C23C) and were provided with water and dry food pellets ad libitum. Before removing the brain mice were sacrificed by cervical dislocation. All procedures of this study including immunizations, blood collection and behavioural studies conformed to the guidelines and were approved by the Animal Care and Use Committee (IACUC) of Palladin Institute of Biochemistry, Kyiv Protocol 1/7-421. Reagents and antibodies All reagents were of chemical grade and were purchased from Sigma-Aldrich unless specially indicated. Recombinant extracellular domain (1C208) of human 7 nAChR was produced as described [12]. Antibodies against 7(179C190), 3(181C192), 4(181C192), 2(190C200) and 4(190C200) nAChR fragments were obtained and characterized by us previously [13C14]. The following antibodies against A have been used: mAb 4G8 (anti-A17C24), mAb 11 A50 B10 (anti-A40), mAb 12F4 (anti-A42), all from Covance, USA; rabbit polyclonal antibody against glial fibrillary acidic protein (GFAP) was from Dako (Agilent Technologies); goat anti-rabbit IgG Alexa 488-labelled was from Invitrogen. Experimental model A group of mice (10 animals) was immunized intraperitoneally with 7(1C208) (50 g per mouse) and boosted every month during 5 months. The first two immunizations were performed with complete Freunds adjuvant (CFA), the third one with incomplete.